Material Science Chapter 1 & 2 by Fatihi Iqbal https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk Introduction to Material Science and The Nature of Materials en-us 2023-04-08 13:29:08 UTC 2025-10-24 23:57:33 UTC hello@padlet.com https://www.theschoolrun.com/sites/theschoolrun.com/files/article_images/what_are_materials.jpg Importance of Materials in Manufacturing fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547611575 What is manufacturing?
- Transformation process
- behavior of the material when subjected to the forces, temperatures, and other processes that determines the success of the operation.

]]> 2023-04-08 13:36:15 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547611575 Atomic Structure and the Elements fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547612897 atom - the basic structural unit of matter
atoms - positively charged nucleus and surrounded by a sufficient number of negatively charged electrons so the charges are balanced

Elements - 2 families 
1. Metals - left and center of the table
2. Nonmetals - right side
Between them - transition zone containing metalloids / semi-metals]]> 2023-04-08 13:40:44 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547612897 Bonding Between Atoms and Molecules fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547625356 Atoms are held together in molecules by various types of bonds

Primary bonds - associated with formation of molecules
Secondary bonds - associated with attraction between molecules

Primary bonds are much stronger than secondary


Primary bond - Covalent and Ionic
Strong atom-to-atom attractions that involve exchange of valence electrons

Secondary bond - Dipole-dipole, London Force and Hydrogen Bond.]]> 2023-04-08 14:22:18 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547625356 Ionic bond fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547631231 Atoms of 1 element donate their outer electron(s), which are in turn attracted to atoms of some other element to increase electron count in the outermost shell

Properties:
  • Poor ductility
  • Low electrical conductivity

Example: 
  • NaCl
  • MgO
  • CaCl
  • CaO
]]> 2023-04-08 14:41:25 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547631231 Covalent bond fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547964403 Outer electrons are shared between 2 local atoms of different elements 

Properties:
  • High hardness
  • Low electrical conductivity

Example: 
  • Diamond
  • Graphite
  • Water
  • Ammonia




]]> 2023-04-09 12:54:48 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547964403 Metallic bond fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547966148 Sharing of outer shell electrons by all atoms to form a general electron cloud that permeates the entire block

Properties:
  • Good conductor
  • Good ductility
]]> 2023-04-09 13:00:06 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547966148 Secondary bond fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547981828 Attraction forces between molecules
  • No transfer or sharing of electrons in secondary bonding 
  • Bonds are weaker than primary bonds

  1. Dipole forces
  2. London forces
  3. Hydrogen bonding

]]> 2023-04-09 13:39:07 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547981828 Dipole forces fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547987356
  • Molecule compromised of 2 atoms with equal and opposite electrical charges
  • Each molecule therefore forms a dipole that attracts other molecules
    • ]]>     2023-04-09 13:52:57 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547987356     London forces fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547992056 Attractive force between non-polar molecules. Atoms in molecule do not form dipoles

    However, due to rapid motion of electrons in orbit, temporary dipoles form when more electrons are on one side]]>     2023-04-09 14:05:33 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547992056     Hydrogen bond fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547993464
  • Occurs in molecules containing hydrogen atoms covalently bonded to another atom(e.g.,H2O)

    • Since electrons to complete shell of hydrogen atom are aligned on one side of nucleus, opposite side has a net positive charge that attracts electrons in other molecules
    ]]>     2023-04-09 14:09:12 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2547993464     Crystalline structure fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548019376 A crystal system where the unit cell is in shape of a cube.

    Structure in which atoms are located at regular and recurring positions in 3 dimensions

    • Unit cell - basic geometric grouping of atom that is repeated
    • The pattern may be replicated millions of times within a given crystal
    • Characteristic structure of virtually all metals as well as many ceramics and some polymers


    When a monomer are arranged in a neat orderly manner, the polymer is crystalline.

    An amorphous solid is a solid in which the molecules have no order and arrangement.
    ]]>     2023-04-09 15:15:55 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548019376     3 crystal structures in metals fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548020209
    • body-centered cubic. Example: Chromium, Iron, Molybdenum, Tungsten
    • face-centered cubic. Example: Aluminum, Copper, Gold, Lead, Silver, Nickel
    • hexagonal close packed. Example: Magnesium, Titanium, Zinc
    ]]>     2023-04-09 15:18:20 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548020209     Defects in crystals fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548030123 often arise due to inability of solidifying material to continue replication of unit cell.

    Imperfections (defects) can also be introduced purposely. E.g., addition of alloying ingredient in metal.

    a) point defects
    b) line defects
    c) surface defects



    ]]>     2023-04-09 15:47:29 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548030123     Point defect fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548032633 involving either a single atom or a small number of atoms

    • vacancy
    • ion-pair vacancy
    • interstitialcy
    • displaced ion (Frenkel Defect)

    ]]>     2023-04-09 15:55:43 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548032633     Line defects fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548035089 Connected group of point defects that forms a line in the lattice structure

    Most important line defect is a dislocation, dislocation can take 2 forms:

    • Edge dislocation - Edge of an extra plane of atoms that exists in the lattice
    • Screw dislocation - Spiral within the lattice structure wrapped around an imperfection line, like a screw is wrapped around its axis.
    ]]>     2023-04-09 16:03:03 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548035089     Surface defects fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548037005 extend in 2 directions to form a boundary

    E.g:
    External : the surface of a crystalline object is an interruption in the lattice structure
    Internal: grain boundaries are internal surface interruptions]]>     2023-04-09 16:09:23 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548037005     Elastic strain fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548040862 when a crystal experiences a gradually increasing stress, it 1st deforms elastically

    a) original lattice
    b) elastic deformation, no permanent change in positions of atoms]]>     2023-04-09 16:21:00 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548040862     Plastic strain fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548044520 If the stress is higher than forces holding atoms in their lattice positions, then a permanent shape change occurs 

    Plastic deformation (slip), in which atoms in the crystal lattice structure are forced to move to new "homes“]]>     2023-04-09 16:34:18 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548044520     Effect of dislocations on strain fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548048779 in the series of diagrams, the movement of the dislocation allows deformation to occur under a lower stress than in a perfect lattice]]> 2023-04-09 16:47:22 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548048779 Slip on a macroscopic scale fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548053237 Good news in manufacturing - the metal is easier to form.
    Bad news in design - the metal is not as strong as the designer would like]]>     2023-04-09 17:00:46 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548053237     Twinning fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548054821 A second mechanism of plastic deformation in which atoms on one side of a plane (the twinning plane) are shifted to form a mirror image of the other side.]]> 2023-04-09 17:05:53 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2548054821 Polycrystalline Nature of Metals fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2551666072 grains - millions of individual crystals that may contain in a block of metal

    the structure is called polycrystalline

    ]]>     2023-04-12 13:58:46 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2551666072     Non-crystalline (Amorphous) Structures fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2551691624 Example: Water and air

    A metal loses its crystalline structure when melted

    Some engineering materials have non-crystalline forms in their solid state
    • Glass
    • Many Plastics
    • Rubber

    Features
    1. Absence of long-range order in the molecular structure
    2. Differences in melting and thermal expansion characteristics

    Difference in structure between crystalline and non-crystalline materials :-
    • Crystal structure is regular, repeating; non-crystalline structure is less tightly packed and random

    ]]>     2023-04-12 14:14:21 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2551691624     Volumetric Effects fatihiiqbal0204 https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2551694253 Characteristic change in volume for a pure metal (a crystalline structure), compared to same volumetric changes in glass (a non-crystalline structure)]]> 2023-04-12 14:15:51 UTC https://padlet.com/fatihiiqbal0204/ldpd3ahuho1ioxzk/wish/2551694253